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How can I resolve the following error message 'WorkBench Error: Could not register files of type:Udflib' or 'Failed in handling Fluent message'?

If you have a UDF with your Fluent simulation, and your Fluent is within WB. The UDF has to be put under FFF/MECH directory, where the .msh file is saved, rather than FFF/Fluent directory. Unfortunately, when compiling the UDF, WB first goes to FFF/Fluent directory to search for the C source. One needs to browse it to FFF/MECH and put c source over there.